/**
 * @author skoon
 */
Array.prototype.union = function() {
	var numOfArrays = arguments.length;
	var newArray = [].concat(this);
	for(var i=0; i<numOfArrays;i++){
		newArray.concat(arguments[i]);
	}
	var unioned = [];
	var newArrayLength = newArray.length;
	for(var c=0;c<newArrayLength;c++) {
		for(var d=c+1;c<newArrayLength;d++) {
			if(newArray[c] === newArray[d]) {
				d = ++c;
			}
		}
		unioned.push(newArray[i]);
	}
	return unioned;
};

String.prototype.isEmpty = function() { return (this == ""); };
